126 ON THE BATRACHIA AND REPTILIA OF COSTA RICA. 



and an accessory anterior portion. The former commences above a point a little 

 in front of the anterior margin of the meatus auditorius, and extends upwards and 

 backwards to a subacute termination. The posterior border descends in an open 

 sigmoid to the nape of the neck to a point a little behind the angle of the jaws. 

 It is covered with large thin smooth scales, and its borders are acute. The anterior 

 part of the helmet rises abruptly from a point in line with the posterior border of 

 the orbit, its anterior border sloping backward to the obtuse extremity, which 

 marks the basal third of the principal helmet. It is separated to the base from 

 the latter by a fissure. The top of the head is covered with small scales, which 

 are weakly or not at all keeled. The supraorbitals are smaller than the supraocular 

 row, and weakly keeled ; those covering the occipital protuberance are equal to 

 them and nearly smooth. Three or four rows separate the superciliary series. 

 Two distinct plates precede the nasal plate, the anterior in contact with the corre- 

 sponding one of the opposite side. Labials, counting to the posterior border of 

 the eye, seven above and seven below. The anterior three infralabials in contact 

 with the inferior labials. Loreal rows four. 



The dorsal scales are smaller than the ventral, but little larger than the lateral, 

 and faintly keeled. Those of the upper surfaces of the limbs are as large as the 

 abdominal and strongly keeled. The dorsal crest is highest behind the middle ; 

 its elevation exceeds that of the body by one-third; it is supported by fifteen rays. 

 The scales covering it are smooth. The caudal crest is also elevated, and includes 

 fifteen rays ; it is covered by thin subequal scales, of which there are eight in a 

 vertical row. Scales of the tail strongly keeled below, weakly keeled elsewhere. 

 The fore foot is rather short ; the ends of the metacarpals mark the muzzle when 

 the limb is extended; the same point is reached by the ends of the basal phalanges 

 of the extended hind limb. 



Color everywhere green, becoming blue on the different crests. No longitudinal 

 or transverse bands on the head, body, or throat. A row of distant round yellow 

 spots from the axilla to the groin, and a similar row along the upper side of the 

 back, which is wanting in some specimens. Various scales of the helmet and 

 crests are paler than the others. Three vertical pale-bordered black spots on the 

 dorsal crest, which may be obsolete in some individuals. Crested part of the tail 

 green, the remainder yellowish, with brown rings to the end of the proximal two- 

 thirds. 



M. 

 Total length (25.75 inches) 655 



Length to vent .......... .177 



" to axilla 090 



